Prefabricated underground substation structure and construction method thereof

Abstract

The application discloses an assembled underground transformer substation structure and a construction method thereof, and belongs to the field of underground transformer substations.The structure comprises a horizontal main support system and a column system.The horizontal main support system comprises horizontal main beams;all the horizontal main beams are used as horizontal inner supports during a foundation pit excavation process;the column system comprises first frame columns provided with column piles at lower ends in a frame structure;the first frame columns each comprise a steel pipe outer wall and are fixedly connected with corresponding horizontal main beams;each group of horizontal main beams is connected with a foundation pit enclosure structure through horizontal ring beams of corresponding layers;and a composite inner lining wall is arranged between every two layers of horizontal ring beams and close to the foundation pit enclosure structure.During construction, the foundation pit enclosure structure and the column system are firstly constructed, then the horizontal main beams and the composite inner lining wall are arranged, after pouring a bottom plate, remaining frame columns, steel secondary beams, stairs and structure plates of each layer are constructed from bottom to top, and finally, an aboveground structure is constructed.The application not only reduces envelope working conditions in a design stage, but also shortens a construction period and reduces engineering investment.

Description

Technical Field

[0001] This invention relates to the field of substation construction technology, and in particular to prefabricated underground substation structures and their construction methods. Background Technology

[0002] Currently, the construction of underground substations typically employs the open-cut method. Its design and construction process is divided into two phases: 1) the excavation phase and 2) the main structure re-construction phase. The retaining structures installed during the excavation phase are usually only temporary (1-2 years). The retaining piles or diaphragm walls may or may not participate in the load-bearing capacity of the main structure during its permanent service life, depending on the design scheme. Horizontal internal supports (concrete or steel supports) often need to be staggered from the floor slabs of the underground main structure at different elevations. They are installed sequentially from top to bottom during the excavation phase and removed sequentially from bottom to top during the main structure re-construction phase. The horizontal internal supports and vertical lattice columns formed in the first phase become obstacles in the second phase. This "build first, dismantle later" approach, to some extent, wastes project investment, prolongs the construction period, increases construction difficulty, and is ineffective in controlling deformation of the excavation pit and surrounding environment.

[0003] In response to the aforementioned problems in the two-stage design and construction, the engineering community proposed the full reverse construction method. However, the full reverse construction method also has problems such as inconvenience in excavation and complex nodes. In addition, the construction process of underground substations itself has the following characteristics: the floor slabs are constructed in reverse along with the foundation pit excavation, which is quite difficult.

[0004] (1) The electrical equipment is densely arranged, there are many openings in the structural floor slab, the structural layout of different rooms is not regular, and the reverse construction of the floor slab is relatively complicated.

[0005] (2) The project construction has the situation of "civil engineering first, followed by electrical renovation", and the floor slabs are constructed in reverse order and still need to be reworked later.

[0006] Therefore, how to reduce the envelope conditions in the design phase can greatly shorten the construction cycle and reduce project investment, which has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0007] In view of the above-mentioned deficiencies of the prior art, the present invention provides a prefabricated underground substation structure and its construction method. The purpose is to further leverage the advantages of integrated design in improving efficiency by using prefabricated construction technology, so that the underground substation and its construction are more in line with the industry trend of green construction and smart construction. Key components such as horizontal internal supports and columns are not only part of the enclosure structure, but also part of the permanent use stage of the main structure to achieve permanent-temporary integration. This can not only significantly reduce the envelope conditions in the design stage, but also greatly shorten the construction cycle and reduce project investment.

[0008] To achieve the above object, the present invention discloses a prefabricated underground substation structure, which is a prefabricated frame structure and includes a horizontal main support system and a column system; the horizontal main support system includes horizontal main beams that are grouped and arranged under each structural slab of the underground structure of the substation.

[0009] Among them, all the horizontal main beams serve as horizontal internal supports during the foundation pit excavation process;

[0010] The column system is used to support all the horizontal main beams and includes first frame columns in the frame structure where column piles are provided at the lower ends of all of them;

[0011] Each of the first frame columns includes a steel pipe outer wall, which is fixedly connected to the corresponding horizontal main beam at each structural slab;

[0012] Each group of the horizontal main beams is connected to the foundation pit retaining structure through a horizontal ring beam provided at the corresponding layer;

[0013] At one end of each horizontal main beam connected to the corresponding first frame column and at one end connected to the corresponding horizontal ring beam, a number of first extended longitudinal bars extending outward along the length direction are provided;

[0014] On the side surface of each steel pipe outer wall connected to each horizontal main beam, a steel corbel with a cross-section in the shape of a "field" is provided. The steel corbel is welded to a number of the first extended longitudinal bars of the corresponding horizontal main beam, and after being externally hooped with multiple stirrups, a first cast-in-place section is formed by pouring micro-expansion concrete to achieve the connection;

[0015] At the position where each horizontal ring beam is connected to the corresponding horizontal main beam, connection steel bars corresponding to the corresponding first extended longitudinal bars are provided. After each connection steel bar is connected to the corresponding first extended longitudinal bar, a second cast-in-place section is formed by pouring micro-expansion concrete to achieve the connection;

[0016] Between every two layers of the horizontal ring beams, a laminated inner lining wall is provided near the foundation pit retaining structure;

[0017] The gap between each laminated inner lining wall and the corresponding foundation pit retaining structure is filled with self-compacting concrete by pouring;

[0018] Each laminated inner lining wall is a reinforced concrete precast wall panel, and second extended longitudinal bars extending upward and downward are provided;

[0019] The upper end and the lower end of each second extended longitudinal bar are respectively connected to the vertical "one" - shaped steel bars of the two horizontal ring beams located above and below;

[0020] Each of the vertical "I"-shaped reinforcing bars is connected to the corresponding horizontal ring beam's reinforcing steel structure, and its ends extend vertically toward the corresponding composite inner lining wall.

[0021] Preferably, the foundation pit retaining structure is a diaphragm wall;

[0022] Each of the composite inner lining walls has a smooth surface on the side facing the main structure, and a rough inner lining surface for applying waterproof coating is provided on the surface facing the foundation pit retaining structure, and several inner lining shear studs are provided.

[0023] The foundation pit retaining structure is a cast-in-place reinforced concrete structure. The surface facing the corresponding composite inner lining wall is provided with a retaining rough surface for applying waterproof coating, and several retaining shear stirrups are provided.

[0024] Each of the aforementioned shear reinforcement stirrups is filled with extruded polystyrene board at its closed end.

[0025] Preferably, each of the first frame columns is a steel-concrete composite square column;

[0026] The outer wall of each of the steel pipes is made of Q235 grade or higher steel, and the inside is filled with high-strength concrete of C50 grade or higher.

[0027] Each of the steel brackets extends outward from the outer wall of the corresponding steel pipe by a length of 0.5 meters to 1 meter. It is located inside the upper flange, lower flange, and side flanges. The web has a cross-section in the shape of a cross. Both sides of the vertical web are provided with multiple shear studs in the vertical direction.

[0028] Preferably, at one end of each horizontal main beam connected to the corresponding steel bracket, multiple first extended longitudinal reinforcements extending along the length direction are provided on the upper and lower flanges of the corresponding steel bracket, as well as on the outer surfaces of the side flanges. Multiple stirrups are provided around the corresponding first extended longitudinal reinforcements along their lengths. This section describes "one end of the horizontal main beam connected to the corresponding steel bracket".

[0029] Each of the first extended longitudinal ribs is fixed to the upper surface of the upper flange, the upper surface of the lower flange, and the outer surface of the two side flanges of the corresponding steel bracket by welding.

[0030] Each of the stirrups wraps around all the first extended longitudinal bars of the corresponding first cast-in-place section.

[0031] Preferably, each of the horizontal ring beams is provided with multiple "U"-shaped steel bars at the position where it connects to the corresponding horizontal main beam;

[0032] One end of each of the “U”-shaped steel bars is embedded in the corresponding horizontal ring beam, and the other end extends toward the corresponding horizontal main beam to form the connecting steel bar opposite to the corresponding first extended longitudinal bar.

[0033] Each of the connecting steel bars is mechanically connected to the corresponding first extended longitudinal bar through a grouting sleeve.

[0034] Preferably, the outward extension length of each of the second extended longitudinal bars is 0.6 meters to 1.0 meters; the outward extension length of each of the first extended longitudinal bars is 0.6 meters to 1.0 meters.

[0035] Each of the aforementioned connecting steel bars is connected to the corresponding first extended longitudinal bar, and each of the second extended longitudinal bars is connected to the corresponding vertical "I" shaped steel bar through a grouting sleeve;

[0036] Each of the grouting sleeves is provided with a rubber pad at one end, and a grouting hole and a grout outlet are provided at both ends respectively.

[0037] Preferably, multiple steel secondary beams are provided between every two adjacent horizontal main beams located under the same structural plate;

[0038] Each of the steel secondary beams is provided with a steel tongue and groove at its end;

[0039] Several secondary steel beam shear studs are provided on both sides of the web of each steel tongue and groove, and embedded parts for secondary steel beams are provided at the bottom.

[0040] Each of the horizontal main beams is provided with a groove matching the corresponding steel tongue and groove at the connection position with the corresponding steel secondary beam. The hinge connection with the end of the corresponding steel secondary beam is achieved by placing the corresponding steel tongue and groove in the corresponding groove and grouting for consolidation.

[0041] Preferably, it also includes a base plate; the base plate is a cast-in-place concrete structure with a grouting sleeve embedded inside, through which each of the internal stressed longitudinal reinforcement bars is connected to each of the third extended longitudinal reinforcement bars of the remaining frame columns that do not belong to the column system.

[0042] This invention also provides a construction method for a prefabricated underground substation structure, comprising the following steps:

[0043] Step 1: Construct the foundation pit retaining structure, including the horizontal ring beam, all column piles, and all first frame columns;

[0044] Step 2: Excavate and hoist all the horizontal main beams of each structural slab from top to bottom to serve as horizontal supports during the foundation pit excavation process, and cast in place the first cast-in-place section between each horizontal main beam and the corresponding first frame column, and the second cast-in-place section between each horizontal main beam and the corresponding horizontal ring beam.

[0045] Step 3: Install the composite inner lining wall of each layer from top to bottom, and pour self-compacting concrete to fill the gap between each composite inner lining wall and the foundation pit retaining structure.

[0046] Step 4: Pour the base slab;

[0047] Step 5: Install the remaining frame columns, steel secondary beams, and prefabricated stairs that do not belong to the column system on each floor in sequence from bottom to top, and pour the structural slab on each floor.

[0048] Step 6: Cover the top structural slab with soil and construct the above-ground structure.

[0049] Preferably, the bottom formwork of the structural slab used for casting each layer of the structural slab is connected to the top of the corresponding steel secondary beam by a number of bottom formwork studs;

[0050] Concrete is poured after the corresponding top longitudinal reinforcement bars are laid for each layer of the structural slab.

[0051] The beneficial effects of this invention are:

[0052] This invention selects a portion of the frame beams and frame columns from the underground substation structure and uses them as horizontal internal supports and temporary columns in the foundation pit retaining structure, thus achieving a permanent-temporary combination of components.

[0053] This invention avoids the two-stage design required for retaining structure components and main structure components in the traditional open-cut construction method, and realizes the integrated design of components.

[0054] Moreover, the present invention adopts prefabricated construction technology to further leverage the advantages of integrated design in improving efficiency, making the underground substation structure and its construction more in line with the industry trend of green construction and smart construction.

[0055] This invention can significantly reduce the envelope conditions during the design phase, greatly shorten the construction period, reduce project investment, and lower carbon emissions. Early grid connection and commissioning of substations will also bring significant social benefits.

[0056] The following will further explain the concept, specific structure, and technical effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Attached Figure Description

[0057] Figure 1 A schematic diagram of an embodiment of the present invention is shown.

[0058] Figure 2 This is a plan view of the connection node between the column system and the horizontal main support system in one embodiment of the present invention.

[0059] Figure 3 Elevation view of the connection node between the column system and the horizontal main brace system in an embodiment of the present invention.

[0060] Figure 4 Elevation view of the "field"-shaped steel bracket in an embodiment of the present invention.

[0061] Figure 5 Elevation view of the connection node between the horizontal ring beam and the horizontal main brace system in an embodiment of the present invention.

[0062] Figure 6 Schematic diagram of the connection between the horizontal ring beam and the reinforcement of the composite lining wall in an embodiment of the present invention.

[0063] Figure 7 Schematic diagram of the connection between the horizontal ring beam and the reinforcement of the horizontal main brace system in an embodiment of the present invention.

[0064] Figure 8 Elevation view of the connection node between the foundation pit retaining structure and the composite lining wall in an embodiment of the present invention.

[0065] Figure 9 Schematic diagram of the composite lining wall in an embodiment of the present invention.

[0066] Figure 10 Schematic diagram of the shear-resistant stirrups and the extruded plastic board in an embodiment of the present invention.

[0067] Figure 11 Elevation view of the connection node between the horizontal main brace system and the steel secondary beam in an embodiment of the present invention.

[0068] Figure 12 Schematic diagram of the steel secondary beam in an embodiment of the present invention.

[0069] Figure 13 Right elevation view of the connection node between the horizontal main brace system and the steel secondary beam in an embodiment of the present invention.

[0070] Figure 14 Elevation view of the connection node between the steel truss floor slab and the steel secondary beam in an embodiment of the present invention.

[0071] Figure 15 Elevation view of the connection node between the frame column and the structural floor slab in an embodiment of the present invention.

[0072] Figure 16 Schematic diagram of the connection between the frame column and the reinforcement of the structural floor slab in an embodiment of the present invention.

[0073] Figure 17 Schematic diagram showing the state of completion of the foundation pit retaining structure, all column piles and the first frame column in an embodiment of the present invention.

[0074] Figure 18This diagram illustrates the state of all horizontal main beams after the completion of the first underground structural slab in one embodiment of the present invention.

[0075] Figure 19 This diagram illustrates the state of all horizontal main beams in a completed underground second-floor structural slab according to an embodiment of the present invention.

[0076] Figure 20 This diagram illustrates the state of all horizontal main beams in a completed underground third-floor structural slab according to an embodiment of the present invention.

[0077] Figure 21 This diagram illustrates the state of the completed composite inner lining wall and the gap between it and the foundation pit retaining structure, as well as the bottom slab pouring, in one embodiment of the present invention.

[0078] Figure 22 This diagram illustrates the state of construction of the remaining frame columns, steel secondary beams, stairs, and structural slab pouring on the third underground floor, which is not part of the column system, in one embodiment of the present invention.

[0079] Figure 23 This diagram illustrates the state of construction of the remaining frame columns, steel secondary beams, stairs, and structural slab pouring on the second underground floor, which is not part of the column system, in one embodiment of the present invention.

[0080] Figure 24 This diagram illustrates the state of construction of the remaining frame columns, steel secondary beams, stairs, and structural slab pouring on the first underground floor, which are not part of the column system, in one embodiment of the present invention. Detailed Implementation

[0081] Example: Figures 1 to 16 As shown, the prefabricated underground substation structure is a prefabricated frame structure, including a horizontal main support system and a column system; the horizontal main support system includes horizontal main beams 2 arranged in groups under the structural slabs 13 of each floor of the underground substation structure.

[0082] Among them, all horizontal main beams 2 serve as horizontal internal supports during the foundation pit excavation process;

[0083] The column system is used to support all horizontal main beams 2, including all first frame columns 1 with column piles 17 at their lower ends in the frame structure;

[0084] Each first frame column 1 includes a steel pipe outer wall 11, which is fixedly connected to the corresponding horizontal main beam 2 at each layer of structural slab 13;

[0085] Each set of horizontal main beams 2 is connected to the foundation pit retaining structure 8 through horizontal ring beams 6 set in the corresponding layer;

[0086] At one end where each horizontal main beam 2 is connected to the corresponding first frame column 1 and at one end where it is connected to the corresponding horizontal ring beam 6, a number of first extended longitudinal bars 22 extending outward along the length direction are provided.

[0087] On the side where the outer wall 11 of each steel pipe is connected to each horizontal main beam 2, a steel corbel 3 with a cross-section in the shape of a Chinese character 'field' is provided. The steel corbel 3 is welded to a number of first extended longitudinal bars 22 of the corresponding horizontal main beam 2, and after being externally hooped with multiple stirrups 23, the first cast-in-place section 41 is formed by pouring micro-expansion concrete to achieve the connection.

[0088] At the position where each horizontal ring beam 6 is connected to the corresponding horizontal main beam 2, connecting bars corresponding to the corresponding first extended longitudinal bars 22 are provided. After each connecting bar is connected to the corresponding first extended longitudinal bar 22, the second cast-in-place section 42 is formed by pouring micro-expansion concrete to achieve the connection.

[0089] Between every two layers of horizontal ring beams 6, a laminated inner lining wall 7 is provided near the foundation pit retaining structure 8.

[0090] The gap 9 between each laminated inner lining wall 7 and the corresponding foundation pit retaining structure 8 is filled with self-compacting concrete by pouring.

[0091] Each laminated inner lining wall 7 is a precast reinforced concrete wall panel, and second extended longitudinal bars 71 extending upward and downward are provided.

[0092] The upper end and the lower end of each second extended longitudinal bar 71 are respectively connected to the vertical 'one'-shaped bars 62 of the two horizontal ring beams 6 located above and below.

[0093] Each vertical 'one'-shaped bar 62 is connected to the steel bar structure inside the corresponding horizontal ring beam 6, and the end portions all extend in the vertical direction towards the corresponding laminated inner lining wall 7.

[0094] In practical applications, each horizontal main beam 2 of each structural slab of the underground substation structure is fixed to the first frame column 1 of the column system, and the lower end of each first frame column 1 of the column system is inserted into the corresponding column pile 17, and the horizontal main bracing system is supported by the first frame column 1.

[0095] In the present invention, the horizontal main bracing system is connected to the foundation pit retaining structure 8 through the horizontal ring beam 6, and a laminated inner lining wall 7 is provided between every two layers of horizontal ring beams 6, so that the laminated inner lining wall 7 and the foundation pit retaining structure 8 form a composite wall to jointly bear the load, realizing the 'integration of two walls'.

[0096] Since the composite inner lining wall 7 uses precast reinforced concrete wall panels, and after the two walls are combined with the foundation pit retaining structure 8, only the outer longitudinal reinforcement participates in bending resistance. Therefore, only a single layer of bidirectional reinforcement is configured inside, and the upper and lower ends are respectively provided with second extended longitudinal reinforcement 71. The second extended longitudinal reinforcement 71 is connected to the vertical "I" shaped reinforcement 62 of the two horizontal ring beams 6 above and below.

[0097] This invention allows some of the frame beams and columns of the main structure to directly serve as horizontal internal supports and columns during the foundation pit excavation stage, thus avoiding the need to replace supports and cut off columns, achieving a combination of permanent and temporary structures.

[0098] Compared with existing technologies, the present invention exhibits less surface subsidence and less deformation of the retaining structure, and the foundation pit stability coefficient is close to that of existing technologies.

[0099] Moreover, combining prefabricated technology can further leverage the advantages of integrated construction in improving efficiency.

[0100] Compared to the two-stage construction of the main structure in existing technologies, the construction of the main structure in this invention is closer to a process of "completing" the main frame.

[0101] This invention proposes the design and construction of several key nodes under the prefabricated process.

[0102] In particular, for general 110kV underground substations, the construction period of the main structure can be reduced by about 5 months after adopting this invention. It has advantages in initial investment and total life cycle investment. The social benefits brought by the early grid connection and commissioning of the substation are obvious. The construction process is more in line with green construction and smart construction.

[0103] In some embodiments, the foundation pit retaining structure 8 is a diaphragm wall; the thickness is generally between 0.8m and 1.2m, and some are even thicker, mainly related to the depth of the foundation pit and the stress, and the insertion ratio is generally between 0.8 and 1.2.

[0104] Each composite inner lining wall 7 has a smooth surface on the side facing the main structure, and a rough inner lining surface 73 for applying waterproof coating on the surface facing the foundation pit retaining structure 8, and is provided with several inner lining shear studs 72.

[0105] The foundation pit retaining structure 8 is a cast-in-place reinforced concrete structure. The surface facing the corresponding composite inner lining wall 7 is provided with a retaining rough surface 83 for applying waterproof coating, and a number of retaining shear stirrups 81 are provided.

[0106] Each shear stirrup 81 of the enclosure is filled with extruded polystyrene board 82 at its closed end.

[0107] In practical applications, several shear studs 72 are set on the rough surface 73 of the lining, several shear stirrups 81 are set on the foundation pit retaining structure 8, and the gap 9 between the foundation pit retaining structure 8 and the composite inner lining wall 7 is filled with self-compacting concrete, which can achieve effective interlocking between the foundation pit retaining structure 8 and the composite inner lining wall 7.

[0108] In some embodiments, each first frame column 1 is a steel-concrete composite square column;

[0109] The outer wall 11 of each steel pipe is made of Q235 grade or higher steel, and the inside is filled with high-strength concrete 12 of C50 grade or higher.

[0110] Each steel bracket 3 extends outward from the corresponding outer wall 11 of the steel pipe by a length of 0.5 meters to 1 meter. It is located inside the upper flange, lower flange and side flanges. In the web with a cross-section of "+", multiple shear studs 31 are provided on both sides of the vertical web in the vertical direction.

[0111] In practical applications, each first frame column 1 of the column system is controlled by a compression-bending member.

[0112] In some embodiments, each horizontal main beam 2 is connected to the corresponding steel bracket 3 at one end, and the upper surface of the upper flange, the upper surface of the lower flange, and the outer surface of the two side flanges of the corresponding steel bracket 3 are provided with multiple first extended longitudinal ribs 22 extending along the length direction. Multiple stirrups 23 are provided around the corresponding first extended longitudinal ribs 22 corresponding to the length of the first extended longitudinal ribs 22.

[0113] Each first extended longitudinal rib 22 is fixed to the upper surface of the upper flange, the upper surface of the lower flange, and the outer surface of the side flanges of the corresponding steel bracket 3 by welding.

[0114] Each stirrup 23 is wrapped around all the first extended longitudinal bars 22 of the corresponding first cast-in-place section 41.

[0115] In some embodiments, each horizontal ring beam 6 is provided with multiple "U"-shaped steel bars 61 at the position where it connects to the corresponding horizontal main beam 2;

[0116] One end of each "U"-shaped steel bar 61 is embedded in the corresponding horizontal ring beam 6, and the other end extends towards the corresponding horizontal main beam 2 to form a connecting steel bar opposite to the corresponding first extended longitudinal bar 22.

[0117] Each connecting steel bar is mechanically connected to the corresponding first extended longitudinal bar 22 through a grouting sleeve 5.

[0118] In some embodiments, each of the second extended longitudinal ribs 71 extends outward by a length of 0.6 meters to 1.0 meters; each of the first extended longitudinal ribs 22 extends outward by a length of 0.6 meters to 1.0 meters.

[0119] Each connecting steel bar is connected to the corresponding first extended longitudinal bar 22, and each second extended longitudinal bar 71 is connected to the corresponding vertical "I" shaped steel bar 62 through a grouting sleeve 5.

[0120] Each grouting sleeve 5 is equipped with a rubber pad 51 at its end, and grouting holes 52 and grout outlet holes 53 are respectively provided at both ends.

[0121] In some embodiments, multiple steel secondary beams 10 are provided between every two horizontal main beams 2 that are adjacent and located under the same structural plate 13;

[0122] Each steel secondary beam 10 is provided with a steel tongue and groove 101 at its end;

[0123] Several steel secondary beam shear studs 102 are provided on both sides of the web of each steel tongue and groove 101, and steel secondary beam embedded parts 103 are provided at the bottom.

[0124] Each horizontal main beam 2 is provided with a groove 24 that matches the corresponding steel tongue and groove 10 at the connection position with the corresponding steel tongue and groove 101. The hinge connection with the end of the corresponding steel secondary beam 10 is achieved by placing the corresponding steel tongue and groove 101 in the corresponding groove 24 and grouting to solidify it.

[0125] In some embodiments, a base plate 14 is also included; the base plate 14 is a cast-in-place concrete structure with a grouting sleeve 5 embedded inside, through which each of the internal stressed longitudinal reinforcements 141 is connected to each of the third extended longitudinal reinforcements 151 of the remaining frame columns 15 that do not belong to the column system.

[0126] Each frame column 15 is made of precast reinforced concrete and has several third extended longitudinal bars 151 at its ends; the extension length of each third extended longitudinal bar 151 is 0.6 meters to 1.0 meters.

[0127] like Figure 1 and Figures 17 to 24 As shown, the construction method for prefabricated underground substation structures includes the following steps:

[0128] Step 1: Construct the foundation pit retaining structure 8, including the horizontal ring beam 6, all the column piles 17, and all the first frame columns 1;

[0129] Step 2: Excavate and hoist all the horizontal main beams 2 of each layer of structural slab 13 from top to bottom to serve as horizontal supports during the foundation pit excavation process, and cast in place the first cast-in-place section 41 between each horizontal main beam 2 and the corresponding first frame column 1, and the second cast-in-place section 42 between each horizontal main beam 2 and the corresponding horizontal ring beam 6.

[0130] Step 3: Install the composite inner lining wall 7 of each layer from top to bottom, and pour the gap 9 between each composite inner lining wall 7 and the foundation pit retaining structure 8 using self-compacting concrete.

[0131] Step 4: Pour the base slab 14;

[0132] Step 5: Install the remaining frame columns 15, steel secondary beams 10, and precast stairs 18 that do not belong to the column system in each floor from bottom to top, and pour the structural slab 13 of each floor.

[0133] Step 6: Cover the top of the structural slab 13 with soil and construct the above-ground structure 19.

[0134] In some embodiments, the bottom formwork 131 of the structural slab 13 used for casting each layer of structural slab 13 is connected to the top of the corresponding steel secondary beam 10 by a number of bottom formwork studs 132.

[0135] Concrete is poured after the corresponding top longitudinal reinforcement 133 of each structural slab 13 is laid.

[0136] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A prefabricated underground substation structure, which is a prefabricated frame structure, including a horizontal main support system and a column system; the horizontal main support system includes horizontal main beams (2) arranged in groups under each structural slab (13) of the underground substation structure; characterized in that, All the horizontal main beams (2) serve as horizontal internal supports during the foundation pit excavation process; The column system is used to support all the horizontal main beams (2), including all the first frame columns (1) with column piles (17) at their lower ends in the frame structure; Each of the first frame columns (1) includes a steel pipe outer wall (11), which is fixedly connected to the corresponding horizontal main beam (2) at each structural slab (13); Each group of the horizontal main beams (2) is connected to the foundation pit retaining structure (8) through a horizontal ring beam (6) provided at the corresponding layer; At one end of each horizontal main beam (2) connected to the corresponding first frame column (1) and at one end connected to the corresponding horizontal ring beam (6), a number of first extended longitudinal bars (22) extending outward along the length direction are provided; On the side of each steel pipe outer wall (11) connected to each horizontal main beam (2), a steel corbel (3) with a "field" - shaped cross - section is provided. The steel corbel (3) is welded to a number of the first extended longitudinal bars (22) of the corresponding horizontal main beam (2), and after being externally hooped with multiple stirrups (23), micro - expanded concrete is poured to form a first cast - in - place section (41) to achieve the connection; At the position where each horizontal ring beam (6) is connected to the corresponding horizontal main beam (2), connecting bars corresponding to the corresponding first extended longitudinal bars (22) are provided. After each connecting bar is connected to the corresponding first extended longitudinal bar (22), micro - expanded concrete is poured to form a second cast - in - place section (42) to achieve the connection; Between every two layers of the horizontal ring beams (6), a composite lining wall (7) is provided near the foundation pit retaining structure (8); The gap (9) between each composite lining wall (7) and the corresponding foundation pit retaining structure (8) is filled with self - compacting concrete; Each composite lining wall (7) is a precast reinforced concrete wall panel, provided with second extended longitudinal bars (71) extending upward and downward; The upper and lower ends of each second extended longitudinal bar (71) are respectively connected to the vertical "one" - shaped steel bars (62) of the two horizontal ring beams (6) located above and below; Each vertical "one" - shaped steel bar (62) is connected to the steel bar structure inside the corresponding horizontal ring beam (6), and the ends all extend along the vertical direction towards the corresponding composite lining wall (7); Each first frame column (1) is a concrete - filled steel square column; Each steel pipe outer wall (11) is made of steel with a grade of Q235 or above, and the inside is filled with high - strength concrete (12) with a grade of C50 or above; The length of each steel corbel (3) extending outward from the corresponding steel pipe outer wall (11) is 0.5 meters to 1 meter. Inside the upper flange, lower flange and two side wing flanges, in the web with a "cross" - shaped cross - section, multiple shear studs (31) are provided on both sides of the vertical web along the vertical direction; At the position where each horizontal ring beam (6) is connected to the corresponding horizontal main beam (2), multiple "U" - shaped steel bars (61) are provided; One end of each of the "U"-shaped steel bars (61) is embedded in the corresponding horizontal ring beam (6), and the other end extends toward the corresponding horizontal main beam (2) to form the connecting steel bar opposite to the corresponding first extended longitudinal bar (22); Each of the connecting steel bars is mechanically connected to the corresponding first extended longitudinal bar (22) through a grouting sleeve (5); Each of the second extended longitudinal bars (71) extends outward by a length of 0.6 meters to 1.0 meters; each of the first extended longitudinal bars (22) extends outward by a length of 0.6 meters to 1.0 meters; Each of the connecting steel bars is connected to the corresponding first extended longitudinal bar (22), and each of the second extended longitudinal bars (71) is connected to the corresponding vertical "I" shaped steel bar (62) by a grouting sleeve (5); Each of the grouting sleeves (5) is provided with a rubber pad (51) at its end, and grouting holes (52) and grout outlet holes (53) are provided at both ends respectively.

2. The prefabricated underground substation structure according to claim 1, characterized in that, The foundation pit retaining structure (8) is a diaphragm wall; Each of the composite inner lining walls (7) has a smooth surface on the side facing the main structure, and a rough inner lining surface (73) for applying waterproof coating on the surface facing the foundation pit retaining structure (8), and is provided with a number of inner lining shear studs (72). The foundation pit retaining structure (8) is a cast-in-place reinforced concrete structure. The surface facing the corresponding composite inner lining wall (7) is provided with a retaining rough surface (83) for applying waterproof coating, and a number of retaining shear stirrups (81) are provided. Each of the aforementioned shear reinforcement stirrups (81) is filled with extruded polystyrene board (82) at its closed end.

3. The prefabricated underground substation structure according to claim 1, characterized in that, At one end of each horizontal main beam (2) connected to the corresponding steel bracket (3), the upper surface of the upper flange, the upper surface of the lower flange, and the outer surface of the two side flanges of the corresponding steel bracket (3) are provided with multiple first extended longitudinal bars (22) extending along the length direction, and multiple stirrups (23) surrounding the corresponding first extended longitudinal bars (22) are provided with the length of the corresponding first extended longitudinal bars (22). Each of the first extended longitudinal ribs (22) is fixed to the upper surface of the upper flange, the upper surface of the lower flange, and the outer surface of the side flanges of the corresponding steel bracket (3) by welding. Each of the stirrups (23) is wrapped around all the first extended longitudinal bars (22) of the corresponding first cast-in-place section (41).

4. The prefabricated underground substation structure according to claim 1, characterized in that, Multiple steel secondary beams (10) are provided between every two horizontal main beams (2) that are adjacent and located under the same structural plate (13); Each of the steel secondary beams (10) is provided with a steel tongue and groove (101) at its end. Several steel secondary beam shear studs (102) are provided on both sides of the web of each steel tongue and groove (101), and steel secondary beam embedded parts (103) are provided at the bottom. Each of the horizontal main beams (2) is provided with a groove (24) matching the corresponding steel tongue and groove (101) at the connection position with the corresponding steel tongue and groove (101). The hinge connection with the end of the corresponding steel secondary beam (10) is achieved by placing the corresponding steel tongue and groove (101) on the corresponding groove (24) and grouting to solidify it.

5. The prefabricated underground substation structure according to claim 1, characterized in that, It also includes a base plate (14); the base plate (14) adopts a cast-in-place concrete structure with a grouting sleeve (5) embedded inside, and each of the internal stressed longitudinal bars (141) is connected to each of the third extended longitudinal bars (151) of the remaining frame columns (15) that do not belong to the column system through the grouting sleeve (5).

6. The construction method for the prefabricated underground substation structure according to any one of claims 1 to 5, characterized in that, The steps include the following: Step 1: Construct the foundation pit retaining structure (8) including the horizontal ring beam (6), all column piles (17) and all first frame columns (1); Step 2: Excavate and hoist all the horizontal main beams (2) of each layer of structural slab (13) from top to bottom as horizontal internal supports during the foundation pit excavation process, and cast in place the first cast-in-place section (41) between each horizontal main beam (2) and the corresponding first frame column (1), and the second cast-in-place section (42) between each horizontal main beam (2) and the corresponding horizontal ring beam (6). Step 3: Install the composite inner lining wall (7) of each layer from top to bottom, and pour the gap (9) between each composite inner lining wall (7) and the foundation pit retaining structure (8) using self-compacting concrete. Step 4: Pour the base slab (14); Step 5: Install the remaining frame columns (15), steel secondary beams (10), and prefabricated stairs (18) that do not belong to the column system in each floor from bottom to top, and pour the structural slab (13) of each floor. Step 6: Cover the top of the structural slab (13) with soil and construct the above-ground structure (19).

7. The construction method for the prefabricated underground substation structure according to claim 6, characterized in that, The bottom formwork (131) of the structural slab (13) used for casting each layer of the structural slab (13) is connected to the top of the corresponding steel secondary beam (10) by a number of bottom formwork studs (132); Concrete is poured after the corresponding top longitudinal reinforcement (133) of each layer of the structural slab (13) is laid.

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